Reflected electron detector and a scanning electron microscope device using it

Abstract

In a scanning electron microscope device having the plastic scintillator type reflected electron detector 17 that is installed below the front end surface 14a of the object lens 14 to detect reflected electrons from the specimen, the reflected electron detector 17 has the front end portion 38 of its scintillator 17a formed into the semicircular portion 44 having a radius almost equal to the radius of the front end surface 14a of the object lens 14. At least a part of the edge of the semicircular portion 44 is formed with the notched surface 39 that extends along the extension of the inclined surface 14b of the object lens 14. This increases the viewing angle of the optical microscope, which is used to locate the position of the specimen being observed, and also increases the solid angle of the detection plane of the detector with respect to the specimen. The reflected electron detector thus can arrest reflected electrons from the specimen efficiently.

What is claimed is: 
     
       1. A reflected electron detector comprising: a scintillator disposed between an object lens and a specimen to detect reflected electrons;   wherein at least a part of a circumferential edge of the front end portion of the scintillator is formed with a notched surface that extends along an inclined surface of the object lens, the front end portion having an electron beam transmission hole to pass an electron beam therethrough.   
     
     
       2. A reflected electron detector comprising: a scintillator disposed between an object lens and a specimen to detect reflected electrons;   wherein the scintillator has a front end portion thereof formed into a semicircular portion with a radius almost equal to the radius of a front end surface of the object lens and at least a part of a circumferential edge of the front end portion is formed with a notched surface that extends along a frustoconical inclined surface of the object lens, the front end portion having an electron beam transmission hole to pass an electron beam therethrough.   
     
     
       3. A reflected electron detector according to claim 1 or 2, wherein the front end portion of the scintillator has a downwardly expanding recess extending from the electron beam transmission hole. 
     
     
       4. A scanning electron microscope device having the reflected electron detector of claim 1 or 2. 
     
     
       5. A scanning electron microscope device according to claim 4, including an optical microscope. 
     
     
       6. A scanning electron microscope device according to claim 4, including a secondary electron detector. 
     
     
       7. A scanning electron microscope device according to claim 4, including an X-ray detector of an X-ray analyzer.